Protection of submerged wooden piles



July 21, 1964 o. E. LIDDELL PROTECTION OF SUBMERGED WOODEN PILES Filed March 26. 1962 INVENTOR. ORVAL E- LIDDELL BY FULWIDER, MATTINGLY & HUNTLEY ATTORNEYS United States Patent 3,141,366 PRGTECTION 0F SUBMERGED WOODEN FILES (Brval E. Liddell, RD. Box 1533, Avalon, Calif. Filed Mar. 26, 1962, Ser. No. 182,523 4 Claims. (Cl. 61--54) The present invention relates generally to the protection of submerged wooden structures against marine borer attack and specifically to a novel means for indicating the efficacy of a pile protecting barrier sheet structure.

In my Patent No. 3,027,610 issued April 3, 1962., I have disclosed a novel method of arresting or preventing marine borer attack by creating and maintaining an environment of stagnant water around the pile to be protected. The stagnant water is created and maintained by means of a barrier sheet of waterproof material which is wrapped about the piling, with the space between the piling and the sheet being filled with the stagnant water. Although laboratory and field installations of my barrier sheets have conclusively indicated that marine borer life cannot be maintained within the stagnant water-filled space, it is possible that improper application of the barrier sheet, mechanical damage to the barrier sheet or other defects may permit excessive circulation between the space and the ambient water surrounding the pile whereby the necessary stagnant condition could not be maintained.

It is a major object of the present invention to provide a novel test stick for positively providing an indication of the eflicacy of a barrier sheet of the nature disclosed in my aforementioned Patent No. 3,027,610.

The test stick of the present invention eliminates the necessity of periodically removing an installed barrier sheet so as to permit inspection of the portion of the pile encompassed by the barrier sheet. Thus, the test stick of the present invention afi ords economy of time and labor.

Other objects and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the appended drawings wherein:

FIGURE 1 is a side elevational view showing a first form of test stick embodying the present invention permanently installed on a piling in the space between the piling and a barrier sheet;

FIGURE 2 is a side elevational view showing a second form of test stick embodying the present invention;

FIGURE 3 is a side elevational view showing the test stick of FIGURE 2 being installed in the space between a piling and a barrier sheet;

FIGURE 4 is a side elevational view showing the test stick of FIGURES 2 and 3 in its installed position;

FIGURE 5 is a side elevational view showing a third form of test stick embodying the present invention;

FIGURE 6 is a fragmentary horizontal sectional view taken in enlarged scale along line 6-6 of FIGURE 1; and

FIGURE 7 is a fragmentary horizontal sectional view taken in enlarged scale along line 7-7 of FIGURE 4.

In the accompanying drawings I have illustrated my invention as being particularly adapted for application to submerged wooden piles. However, it will appear to those skilled in the art that the principles herein disclosed are not necessarily so limited and can be utilized with certain other types of submerged wooden structures.

Referring to the drawings and particularly FIG- URES 1 and 6 thereof, the first form of test stick T1 embodying the present invention is shown in conjunction with a partially submerged pile P and a barrier B that encompasses the pile P. The barrier sheet B includes a waterproof sheet 10, preferably made of a material such as polyvinyl chloride. This sheet should be substantially waterproof in the sense that while it may be porous, the ratio of volume of pores or interstices to the Volume of mass restricts the circulation of sea water around the encased piling to such an extent that the rate of circulation is less than that required to maintain marine borer life. When the salt, oxygen and organic matter which the borers extract from the sea to sustain themselves are not supplied at a sufliciently high rate, the borers die. The extent to which the rate of circulation must be restricted will vary according to the type of borer, the salt, oxygen and organic matter content of the sea and other local conditions and is therefore subject to many variables.

The sheet 10 of barrier B is generally rectangular, al though it will preferably taper from its upper to its lower edge to conform to the taper of the pile P. The sheet It? has a width throughout its length exceeding the corresponding circumference of the pile. The opposite vertical edges of the sheet 16 are engageable with a vertical pole piece 12 that extends longitudinally of the sheet 10 and generally parallel with the pile P. In installing the barrier B the sheet 10 is arranged about the piling and the pole piece 12 is engaged with the opposite vertical edges of the sheet. The pole piece 12 is then rotated so as to reduce the effective diameter of the space encompassed by the sheet 10 until the sheet engages the pile P in the manner indicated in FIGURES 1 and 6. In this manner there is created a space 14 between the sheet 1t) and the pile P, with circulation of the ambient water 16 surrounding the pile P and such space 14 being restricted. Preferably, the lower end of the sheet 10 will be sealed off from the ambient water 16, as by a suitable sealing band 18. Alternatively, the lower end of the sheet 10 may extend below the mud line 20.

It will be understood that the water within the space 14 will become stagnant and therefore toxic to marine borer life. As noted hereinabove, it is possible that the space 14 may inadvertently become open to circulation with the ambient water 16 because of defects in installation of the barrier B or by virtue of mechanical damage to the barrier B. It is the main purpose of the present invention to provide novel means for indicating whether or not this has occurred. The novel means includes the test stick T-1 shown in FIGURE 1. This test stick is simply a bare elongated wooden element, preferably of the same species as that of the pile P. This test stick T-l is affixed to the pile P within the space 14. In the embodiment of FIGURES 1 and 6 the test stick T-l is afiixed to the piling P by suitable fastening means, such as nails 24. The test stick T-l is untreated and will be subject to any marine borer activity which might be taking place within the space 14. It is desirable that the test stick T1 be arranged at the area wherein it is known that marine borer activity is heaviest for the particular location of the pile P. The length of the test stick should be sufficient to span this area of heaviest marine borer activity. The installation of the test stick T-1 beneath the sheet 10 will create a definite bulge in this sheet. Should the test stick T-l undergo marine borer attack it will of course rapidly deteriorate. Such deterioration may be readily manually detected by feeling the test stick T-1 through the barrier sheet 10 to detect holes, sponginess or the like. It may also be possible to detect deterioration of the test stick T-1 by visual examination. Actual field tests have determined that a bare wooden stick when exposed to marine borer activity in fresh circulating sea water will be completely destroyed within a matter of weeks. It will be understood that the test stick T-l will remain permanently alfixed in operating position so long as the barrier B remains intact.

Referring now to FIGURES 2, 3, 4 and 7 there is shown a second form of test stick T-2 embodying the present invention. The test stick T2 is adapted for use with a barrier B similar to that shown in FIGURES 1 and 6, and like parts of said barrier B bear the same numbers throughout these figures. The test stick T-2 rather than being permanently installed relative to the piling P and the barrier B is removable relative thereto. The test stick T-Z like the test stick T-l is preferably of the same species as the wood of the pile P. Also, the test stick T-2 will be bare and untreated.

The test stick T2 should be of sufiicient length to extend for the full vertical distance of the active marine borer attack zone and additionally should project upwardly relative to the upper end of the barrier B, as indicated at 30 in FIGURE 4. As indicated in FIGURE 7, a generally triangular passage 32 is defined in the space 14 to one side of the pole piece 12. This passage 32 is particularly well adapted to receive the test stick T2. It is important to note that the test stick T-Z may be installed on existing barriers without requiring disassembly of such barriers. Where the available space above the barrier B is limited as by the underside of a pier deck the test stick T-Z should be sufiiciently flexible as to be bendable at the necessary angle to permit insertion into the space 32. After the test strip T2 has been installed it may be held in place by suitable fastening means, such as nails 34 which are driven through the upper end of the test stick and into the piling P above the barrier B.

When it is desired to inspect the test stick T2 the nails 34 are removed. Thereafter, the test stick T-Z may be readily pulled upwardly out of the passage 32. When removed, the test stick T-Z is susceptible of detailed full-length examination. This examination will reveal whether or not any marine borer attack has occurred, as well as the exact location of such attack. After the test stick T-2 has been examined it may be readily reinstalled in its position of FIGURE 4.

Referring now to FIGURE 5, there are certain applications where the top of the barrier may be disposed at an elevation below the surface of the water 16. Where such a barrier B is employed, the upper end of the sheet will be closed as by a sealing band 36. Under these circumstances a third form of test stick T3 will be utilized. The test stick T-3 will be similar to the aforedescribed test sticks, however, its upper end will be disposed below the sealing ring 36. The test stick T-3 is shown held in place by fastening means such as a nail 40 that is driven through the upper end of the test stick and into the pile P. It will be obvious that the test stick T-3 will be installed prior to the time that the sealing band 36 is tightened. The test stick T-3 may be removed for inspection by first loosening the sealing band 36. Thereafter, the nail 40 will be withdrawn and the test stick T-3 pulled upwardly out of the barrier B.

It will be apparent that each of the aforedescribed forms of test stick embodying the present invention permit the efficacy of the barrier to be readily inspected without requiring disassembly of the barrier.

Various modifications and changes may be made with respect to the foregoing detailed description without departing from the spirit of the present invention or the scope of the following claims.

I claim:

1. The combination of a partially submerged wooden pile; a barrier that includes a sheet of waterproof material encompassing said pile to define a generally circumferential space between said pile and said sheet that is filled with stagnant water to prevent marine borer attack on the submerged portion of said pile; and a wooden test stick that is substantially as susceptible to said attack as said pile, said stick being disposed within said space to create a bulge in said sheet and thereby provide an indication of the efiicacy of said barrier sheet.

2. The combination of a partially submerged wooden pile; a barrier that includes a sheet of waterproof mate rial encompassing said pile to define a generally circumferential space between said pile and said sheet that is filled with stagnant water to prevent marine borer attack on the submerged portion of said pile; and a wooden test stick that is substantially as susceptible to said attack as said pile, said stick being secured to said pile within said space so as to eifect outward bulging of said sheet whereby deterioration of said test stick from marine borer attack can be detected without disassembling said barrier.

3. The combination of a partially submerged wooden pile; a barrier that includes a sheet of waterproof ma terial encompassing said pile to define a generally circumferential space between said pile and said sheet that is filled with stagnant water to prevent marine borer attack on the submerged portion of said pile; and an elongated wooden test stick that is substantially as susceptible to said attack as said pile, said stick being disposed within said space to provide an indication of the efficacy of said barrier, said stick being removable upwardly from said space for inspection, with the upper end of said sheet and said test stick extending above the area of said attack.

4. The combination of a partially submerged wooden pile; a barrier that includes a sheet of waterproof material encompassing said pile to define a generally circurnferential space between said pile and said sheet that is filled with stagnant water to prevent marine borer attack on the submerged portion of said pile; and an elongated wooden test stick that is substantially as susceptible to said attack as said pile, said stick being disposed within said space to provide an indication of the efficacy of said barrier, the upper end of said stick extending above the upper end of said sheet whereby said stick is removable upwardly from said space for inspection without disassembly of said barrier and with the upper end of said sheet and said test stick extending above the area of said attack.

No references cited. 

1. THE COMBINATION OF A PARTIALLY SUBMERGED WOODEN PILE; A BARRIER THAT INCLUDES A SHEET OF WATERPROOF MATERIAL ENCOMPASSING SAID PILE TO DEFINE A GENERALLY CIRCUMFERENTIAL SPACE BETWEEN SAID PILE AND SAID SHEET THAT IS FILLED WITH STAGNANT WATER TO PREVENT MARINE BORER ATTACK ON THE SUBMERGED PORTION OF SAID PILE; AND A WOODEN TEST STICK THAT IS SUBSTANTIALLY AS SUSCEPTIBLE TO SAID ATTACK AS SAID PILE, SAID STICK BEING DISPOSED WITHIN SAID SPACE TO CREATE A BULGE IN SAID SHEET AND THEREBY PROVIDE AN INDICATION OF THE EFFICACY OF SAID BARRIER SHEET. 